Mario Williams’ athleticism is so impressive and his potential so appealing that the Houston Texans may pass on Reggie Bush. The New Orleans Saints may take him at No. 2 instead of trading down to acquire additional picks. Or, if he’s still available with the fifth pick, the Green Bay Packers will have to decide between Williams and Ohio State linebacker A.J. Hawk.

Better than Bush? Worth the No. 2 pick? More valuable than Hawk?

Maybe. That’s how much teams think of Williams, the N.C. State defensive end who entered the draft a year early following a 141/2-sack season for the Wolfpack.

“I had a pretty good run there at the end, and I felt my opportunity to go to the next level was pretty good,” he said. “I didn’t want to have something happen next year that might mess up my chances.”

Williams has done nothing in the offseason to mess up his chances of being selected early in Saturday’s NFL Draft.

Since the end of last season, Williams has added 10 pounds to his 6-foot-7 frame (he now weighs 295) and impressed at the NFL combine by running the 40-yard dash in 4.66 seconds and recording a 40.5-inch vertical leap.

Not bad for a player who had only 11 sacks in his first two college seasons.

Williams said he would prefer to play left defensive end but said he can play all over the field — N.C. State used him on both ends of the line and at outside linebacker last year.

“I can play the 3-4 and the 4-3,” he said. “If they want me as a linebacker, I can do that coming off the edge. My main goal coming into this was to be versatile and then let the team that picks me put me where they want to. That’s what it will be about for me — putting me where I fit best.”

The Saints let Darren Howard sign with Philadelphia in free agency but still have Charles Grant and Will Smith to play end. Regardless, if New Orleans is unable to strike a deal to get out of the second spot and opts not to take a quarterback it can deal later in the day, Williams could be its guy.

But only if Houston takes Bush or a quarterback. Yes, the Texans — so the grapevine says — remain torn between Bush and Williams. Only two defensive ends, Courtney Brown in 2000 to Cleveland and Steve Emtman to Indianapolis in 1992, have gone No. 1 overall in the last 15 years. Neither panned out.

In addition to his 141/2 sacks last season, Williams had 24 tackles for lost yardage, which suggests he’s not a one-trick (pass rushing) pony.

“He had some up and down games last year, as most players do, but he’s a tremendously talented kid,” Green Bay general manager Ted Thompson said. “He looks like what you draw up. You want him to get off the bus first.”

After Williams, the next two defensive linemen drafted could be tackles: Oregon’s Haloti Ngata and Florida State’s Brodrick Bunkley. Buffalo will have its pick of the two with the eighth selection. Cleveland reportedly likes Bunkley’s FSU teammate, Kamerion Wimberly, who can play outside linebacker in a 3-4 defense or end in a 4-3 alignment.

Penn State’s Tamba Hali could play end or outside linebacker, and that tweener quality has him going in the late first or early second round. But Hali may be the most fascinating story in the draft.

Born in Liberia, Hali and his family fled the war-torn country and went to Ivory Coast and, in 1994, to the United States. It also was the last time he saw his mother.

“It’s been tough, going through life with your mother and then going through the second half of your 22 years without her,” he said. “You deal with it and work through it. That’s how life is — full of adversity.”

Hali had 11 sacks for the Nittany Lions last year, and scouts point to his height (6-2) and short arms as reasons why he may fall into the second round. But teams are well aware of his background.

“When we interviewed him, I was just overwhelmed not only with his story but the way he told it,” New York Giants general manager Ernie Accorsi said. “He’s such a thoughtful, intellectual, moving person. You could hear a pin drop in our interview room when he was done telling us his story.”